The Senate sergeant at arms and doorkeeper (SAA), elected by the members, serves as the protocol and chief law enforcement officer of the Senate and is the executive officer responsible for most support services in the Senate.

As the Senate's chief law enforcement officer, the SAA supervises the Senate wing of the Capitol, maintaining security in the Capitol and in all the Senate buildings, and controlling access to the Senate Chamber and galleries through a team of doorkeepers. The SAA also protects the senators and can arrest and detain any person violating Senate rules. Additionally, the SAA can compel senators to come to the Senate Chamber to establish a quorum.

As a member of the Capitol Police Board, the SAA also helps to oversee the operations of the United States Capitol Police. Alternating with the House sergeant at arms, the Senate SAA serves as chairman of the Capitol Police Board every other year.